Introduction: Few studies have comprehensively characterized toxic chemicals related to waterpipe use and secondhand waterpipe exposure. This cross-sectional study investigated biomarkers of toxicants associated with waterpipe use and passive waterpipe exposure among employees at waterpipe venues. Method: We collected urine specimens from employees in waterpipe venues from Istanbul Turkey and Moscow Russia and identified waterpipe and cigarette smoking status based on self-report. The final sample ...